||Country|Builder|Location|Ship|Class / type|
|---|---|---|---|---|---|
|6 March|United States|John Roach and Son|Chester, Pennsylvania|City of Rio de Janeiro|Passenger ship|
|13 May|Germany|Kaiserliche Werft Wilhelmshaven|Wilhelmshaven|Bayern|Sachsen-class ironclad|
|13 June|United Kingdom|Royal Dockyard|Devonport, Devon|Pegasus|Doterel-class sloop|
|31 August|United Kingdom|Royal Dockyard|Sheerness|Gannet|Doterel-class sloop|
|23 October|Norway|Karljohansverns Verft|Horten|Nor|Vale-class gunboat|
|1 November|Norway|Karljohansverns Verft|Horten|Brage|Vale-class gunboat|
|9 November|Germany|A. G. Vulcan|Stettin|Württemberg|Sachsen-class ironclad|

Question: count how many different classes of ships were launched.
Answer: 4